Controlling damaging pests on plants grown to provide human food is a constant struggle for growers. Insects can completely destroy a harvest and can cause catastrophic food shortages or financial ruin for the growers. Although many products are effective against insects that damage plants, the products must also be safe enough to be released into the growing environment and safe enough to be applied to parts of the plants that will eventually be consumed.
Organic farming is increasing in popularity. Organic farming restricts the use of compounds that are used for pest control to encourage sustainability and safety. Insecticides can be used in organic farming if they are considered “natural.” Unfortunately, many of the natural insecticides currently available are not potent enough to provide adequate insect control. Further, many of the currently available natural pesticides are not practical to apply or their application is cost prohibitive.
One effective naturally derived insecticide is found in the tissues of many of the plants of the genus Schoenocaulon, commonly referred to as sabadilla . The species with the longest history of use, and the most readily available, is Schoenocaulon officinale. The plant is indigenous to Central and South America and its seeds have been used for centuries for their insecticidal properties. The seeds contain the alkaloids veratridine and cevadine, both of which are known to be active against arthropods.
Usually the dried seeds are ground to a powder and the powder is applied dry or wetted to the insects or their environment. The seeds must be milled into smaller particles in order to be applied to the insects. The milling process usually requires an oil absorbing adjuvant to prevent the seeds from caking. This adjuvant dilutes the alkaloids in the ground seeds. Also, the ground seeds can be difficult to apply to areas in need of treatment because the seed particles and anti-caking adjuvant can clog spraying equipment. Another disadvantage of using ground seeds is that the dust from the seeds can cause eye and nasal irritation. Further, the ground seed powder is often not potent enough to control large infestations.
U.S. Pat. Nos. 2,348,949 and 2,390,911 disclose the use of ground sabadilla seeds with beta-butoxy-beta-prime-thiocyanodiethyl-ether to control houseflies. Further, these patents teach heating the seeds and using them as a powder, or mixing them with kerosene to form a sprayable formulation. Neither of these disclosed mixtures of ground sabadilla seeds would be appropriate for organic farming.
Accordingly, there is a need for new methods of controlling insects. The methods should be potent, safe for growers to apply, safe to beneficial organisms (target specific), and safe for the environment.